Add optional machine-readable output format

[bnjbvr]

No description provided.

[Bromeon]

This would be very nice, especially for CI setups and scripting.

I was thinking about using the application's exit code as well, which is currently used for errors only.
In case you don't want to do that for all cargo machete invocations, what do you think of an approach like:

git diff --exit-code

(doc) which returns 1 on differences and 0 if all is OK?
If there are errors, it could return 2 (or anything non-0), so differentiation is still possible for those needing it.

[bnjbvr]

Would be very nice to have, and I think we could do that on all machete invocations (i.e. not mandating --exit-code). Would you be interested in implementing this?

[Bromeon]

Gladly! I could have a look at it on the weekend 🙂